#define _CRT_SECURE_NO_WARNINGS 1

class Solution
{
public:
    int findKthLargest(vector<int>& nums, int k)
    {
        srand(time(NULL));
        return qsort(nums, 0, nums.size() - 1, k);
    }

    int qsort(vector<int>& nums, int l, int r, int k)
    {
        if (l == r) return nums[l];

        int key = GetRandom(nums, l, r);
        int i = l, left = l - 1, right = r + 1;
        while (i < right)
        {
            if (nums[i] < key) swap(nums[++left], nums[i++]);
            else if (nums[i] == key) i++;
            else swap(nums[--right], nums[i]);
        }

        if (r - right + 1 >= k) return qsort(nums, right, r, k);
        else if (r - left >= k)return key;
        else return qsort(nums, l, left, k - r + left);
    }

    int GetRandom(vector<int>& nums, int left, int right)
    {
        int r = rand();
        return nums[r % (right - left + 1) + left];
    }
};